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Monday, July 14, 2014

Seen too late

On the wide, flat sands of Boundary Bay, residents park their boats helter-skelter, tying them to a variety of home-made anchor points. There is no need for a wharf; some people just wade ashore from a close tie-up, others, anchored farther out, use paddle-boards or small skiffs to reach their boat when the tide is in. The sand is dotted with these contraptions, sometimes a chain attached to something deep in the sand, or an old rope tied to a bucket of cement.

Each of these creates its own mini-environment, catching floating seaweeds or logs, providing holes and crevices for a variety of intertidal critters, and a solid substrate for barnacles and mussels. Sand flows around them as the tide comes and goes, making hills and valleys, semi-permanent tide-pools where a small fish can wait safely through the dry hours.

Walking on the sand at low tide, I veer from one anchor point to the next; no two alike, none uninhabited.

We stopped at this one yesterday:

A half-buried bucketload of cement, with rusted metal fittings, long turned into red stone, encrusted with barnacles and seaweeds.

The "face" of the bucket, with a small log and a deepish pool.

Both Laurie and I poked our cameras into those two holes; none of the photos were any good, but we did see what was inside. They are rusty metal tubes, probably where some sort of fixture to hold a boat was attached. The top one shelters several hermit crabs and snails; a small, green crab guards the door of the lower tube.

"You can't see me; I'm green, and I'm hiding under green seaweed!"*

*(That's assuming that a crab sees colours the same as we do, which is entirely unevidenced.)

On the downstream side of the bucket, the current has hollowed out a pool and a long, shallow valley, paving the valley with broken clamshells.

Refraction through a couple of inches of water.

And where the shells peter out, in a calm backwater, worms keep on feeding while the rest of the beach lies dormant.

These are the largest worm tubes I have seen on the beach, up to 3 inches tall, standing firm.

They remind me of tipsy pilings left behind when an old wharf is demolished. But these have neat holes in the top, and if you look closely at the right moment, transparent tentacles reaching out.

And look again! See that whitish thing near the centre, that square with a tail? I didn't, when I was taking the photos, and it turned up on a half dozen. So I missed out; must be more observant.

The Mud-flat Hooded Shrimp, Nebalia pugettensis!

I last saw one of these 4 years ago. And the one before that was another 4 yearsearlier (Two posts). They're probably plentiful on the beach, but they're usually burrowing in the muck. This may be a dead one, or a molt. The live one I found had blue eyes; the dead ones I'd seen earlier had red eyes.

If you look back at the first photo of the Nebalia, you might see the second one, down by the lower right hand corner, half-hidden behind a blade of eelgrass.

And here's another one:

Very hairy green crab, not bothering to hide. And just below the broken shell at upper left, another Nebalia.

This one has no colour left. It must be a molted carapace and legs.

I hope I don't have to wait another 4 years before I see my next mud shrimp.

1 comment:

I saw one of these last year...or more specifically, stepped on one. Those sharp spines are amazingly stiff, and the entire shrimp was attached to my foot like a cactus. I didn't know what it was (thought it was a crab larva) but now I know!